Epidemiologist answers some common questions about the H1N1 virus
Is it hype, hysteria or common-sense awareness and preparedness, this flu thing?
Ask us next spring, when (we hope) the current flu season peters out -- though even then there still may be no definitive answer to satisfy everyone.
In the meantime, some common questions keep popping up despite the forests of newsprint and hours of broadcast yammering devoted to the onset, spread and impact of 2009 novel H1N1 flu.
Some of the questions and answers seem obvious, and yet ...
Can you get this "swine flu" by eating pork chops?
No, all the experts say. And they feel sorry for the farmers who are losing money on every hog they sell, in part because of the name that was slapped on this particular flu bug (which carries strains of human and bird flu as well as swine flu).
People who study the origins and spread of viruses are looking hard at large factory pig farms as places where human and swine flu viruses mix, despite impressive "Andromeda Strain" bio-security measures designed to keep the two species separated.
"What worries virologists is the mixing of human and swine flu strains -- or, worse, human, swine and bird strains," the Washington Post reported last Sunday. "That can lead to 'reassortment,' in which strands of genetic material are exchanged to yield a new virus, often with behavior not seen in its parents. Those features can include higher contagiousness, rapid growth, the ability to infect the lungs and, most important, an unfamiliar appearance to the immune system."
So, you ask, should you not take the kiddies out to pet pigs at the factory farm?
That's right. Besides, you'd all have to take a shower before entering and another shower after leaving, if the operators let you in, and they won't.
To answer some of the other persistent questions about the flu, we turned to Kirby Kruger, state epidemiologist with the North Dakota Department of Health.
Q. What's the difference between seasonal flu and H1N1 flu?
A. Seasonal influenza refers to the influenza viruses that circulate annually and have been circulating and causing human illness for many years. These viruses often undergo small changes from year to year but are basically the same. The small changes that occur in seasonal influenza are usually enough to require new vaccines be made every year for influenza to provide optimum protection against the viruses. Each year, it is anticipated that three different flu viruses will circulate -- two Type A and one Type B.
Pandemic influenza occurs when either a new influenza virus emerges or a significant change occurs in a seasonal Type A virus and this new virus can cause disease and be spread from person to person. Because pandemic flu viruses are new, most of the population has not been exposed and therefore most people are susceptible.
Q. Once I'm exposed to the H1N1 virus, how long before symptoms appear?
A. One to three days, seven days maximum.
Q. If I'm feeling achy and tired and have a cough and sore throat -- but no fever -- does that mean I don't have H1N1?
A. A person may have novel H1N1 and some of the other symptoms and not have a fever. Reports from the Southern Hemisphere during the last influenza season there indicate that a significant percentage of those infected with H1N1 did not report fever. Studies of seasonal influenza suggest that viral shedding correlates with fever. People who do not have fever may not be shedding virus as heavily as those who do. We have defined influenza-like illness as having a fever greater than 100 degrees with a cough or sore throat. This case definition is fairly specific during the influenza season. Because many viruses that circulate at the same time as influenza can cause similar symptoms, it is difficult to provide exact guidance. The guidance that we provide to the public is not expected to stop all transmission but to keep those most likely to transmit the virus at home until they are much less likely to transmit it -- 24 hours after fever without fever reducing medication.
Q. Why are pregnant women a priority group for vaccination against H1N1?
A. Pregnant women are at increased risk for complications from influenza and are recommended to receive vaccine every influenza season. A study recently published showed that about one-third of pregnant women who had novel H1N1 were hospitalized.
Q. Why are young children a vaccination priority group?
A. Likewise, children younger than 5 years of age, especially those younger than 2 years, are at increased risk for complications.
Q. Why aren't labs testing specifically for 2009 novel H1N1 flu and instead telling people that they have Type A flu and "probably" the new H1N1?
A. The only laboratory in North Dakota that can confirm novel H1N1 is the laboratory at the North Dakota Department of Health. We do not have the capacity to test every ill person for influenza, nor is that needed to get an understanding of what is happening in the state. By testing hospitalized cases and selectively testing other patients, we are able to get a pretty good feel for the extent of disease and the types of virus that are circulating in the state.
Much of the testing that is being done in the state is being done by the health care provider in the form of rapid tests. These tests often can only tell if the person has influenza or if they have influenza A or B. None of these rapid tests can differentiate between seasonal and novel H1N1 influenza. However, novel H1N1 is the predominate influenza virus circulating in North Dakota and the U.S., so those who have a rapid test that is positive likely have novel H1N1.
Q. If most people getting sick with flu-like symptoms aren't being tested, what good are the numbers the state is putting out?
A. The numbers allow us to track trends, monitor activity in different geographic areas of the state and compare statistics to previous years and other geographic areas and populations. Furthermore, testing is needed to monitor what types of influenza viruses are circulating in the state.
Q. What does flu "attack rate" mean, and how does the H1N1 flu attack rate compare to seasonal flu and previous flu pandemics?
A. The attack rate refers to the proportion of people in a community who become ill with influenza. Usually, for seasonal influenza, this is around 10 percent to 15 percent. For a pandemic, we can expect attack rates where 30 percent or more of the population become ill.
Q. If I think I have H1N1 flu but I'm not sick enough to seek medical treatment, is there a way for me to get a diagnosis so I know?
A. Basically, the answer is no. If you do become ill with fever and respiratory symptoms, there is a higher likelihood that it is novel H1N1.
Q. If I get sick with flu, do I have immunity or do I still need to be vaccinated?
A. You likely will have immunity from the virus that infected you. The question is, do you know for sure what caused your illness? With most cases now being diagnosed based on symptoms alone or symptoms and a non-specific test, most people being told they had H1N1 don't know for sure. We recommend that people who want to be vaccinated do so regardless of previous illness history when vaccine becomes available for them.
Q. I keep seeing and hearing statements that the flu vaccine could be more dangerous than getting the flu, especially since most cases seem to be mild. What's the truth?
A. That is not true. The rate of any serious side effects from being vaccinated is very small compared to the rate of severe influenza in the population. The vaccine is safe, with side effects being the same as seasonal influenza vaccine.
Q. If I took Tamiflu or another anti-viral medication, do I still need to be vaccinated?
Q. If I have a mild case of flu, then get better but the symptoms come back, is that bad? What should I do?
A. Seek medical care. This pattern may indicate a secondary infection with another germ.
Q. Isn't all this attention to H1N1 out of proportion to the risk to public health, since thousands of people in the U.S. die from seasonal flu every year?
A. Although overall, the severity of illness for the novel H1N1 virus seems to be similar, there are some differences. This is a new virus and basically the whole population is at risk. We have a vaccine, but it is being released at a slower rate than anticipated. This virus appears to be impacting young adults and children more. Although many who have died from novel H1N1 flu had underlying conditions, in at least a third of the childhood deaths, no underlying health conditions were recognized.
Q. Can I catch the H1N1 flu and the seasonal flu at the same time? How much more dangerous would that be?
A. Yes, it is possible, but not probable. I don't know how much more dangerous that would be.
Q. If I'm vaccinated for H1N1, am I protected for life?
A. Not likely for life, but at least a year, which should cover you until the next influenza season when you would need another flu shot that covers the changes made in the virus over the preceding year.
Q. I hardly ever get sick during flu season. Should I still get vaccinated or, because of the limited vaccine available, step aside so someone else can get it?
A. If you are healthy, this is a personal choice. If you have underlying health conditions, you should be vaccinated or at the very least talk to your doctor before choosing not to be vaccinated. Although vaccine is being released at a slower rate than anticipated, there should be enough vaccine for everyone who wants to be vaccinated -- eventually.
Q. What's the greatest myth, falsehood or misconception circulating about H1N1 now?
A. The most common questions seem to be on vaccine safety. The vaccine is made the same way as seasonal flu vaccine and is tested the same way. This vaccine is as safe as seasonal influenza vaccine.